Aggravating Factors of Asthma in a Rural Environment Study (AFARE)

摘要

Background: In the U.S, asthma prevalence and morbidity are as high or higher for minority and low income rural children compared to urban children. Environmental factors associated with agriculture may be important but data are few. Objectives: To establish a longitudinal asthma cohort and residential ambient air monitoring network in a low income population that resides in an area of dense crop and dairy production. Methods: Within a community based participatory research partnership (El Proyecto Bienestar), fifty nine school age children with asthma were enrolled for 24 month assessment of asthma status including daily peak flow monitoring and biweekly composite scores of asthma (ACQ - Asthma Control Questionnaire). A novel active air sampler was constructed of multiple sampling media connected to individual critical orifices and a rotary vane vacuum pump. Fourteen were deployed at participant households in the last 18 months of the study. Collection of 24 hour samples every six days was done for determination of NH3, PM 2.5, total dust, endotoxin, and pesticides. Results: Fifty children provided data over more than 12 months. Peak flow measures were reduced for 18% of measures. Average ACQ scores for 13 subjects (26%) indicated poor asthma control (＞ 0.75). Scores showed spatial and temporal trends. Samplers performed well with accepted flow rates and were rated as not bothersome by households. Preliminary measures of mean and standard deviation of PM 2.5 and NH3 concentrations were 15.5 ± 13.2 μg/m3 and 30.1± 38.5 ppb, respectively. Conclusions: Longitudinal assessment of asthma in a hard to reach population can be successful in a community based framework. Observed ambient PM 2.5 concentrations exceed US EPA regulatory standards. Ambient ammonia concentrations exceed levels observed in a previous study in this region. The data bank of air samples and health outcomes provides a unique opportunity to evaluate the role of community air quality on asthma health in a rural context.